I. Benson, T. Helser, Giovanni Marchetti, B. Barnett
Our novel approach for fish age prediction uses quantitative analysis of Fourier transform near-infrared (FT-NIR) spectra of otoliths by means of multimodal convolutional neural networks (MMCNN). We integrate two key data modalities that are related to fish ages: the entire range of wavenumbers of FT-NIR spectra and corresponding biological and geospatial data for nearly 9000 walleye pollock ( Gadus chalcogrammus) specimens. The proposed model extracts informative spectral features automatically and elucidates hidden structural relationships associated with fish growth to improve age predictions. Absorbance associated with 7000 to 4000 cm−1 wavenumbers had the highest influence on model predictions followed by fish length, latitude, depth, and temperature. The optimal model resulted in good overall performance with an R2 of 0.93 and RMSE of 0.83 for training data set and R2 of 0.92 and RMSE of 0.91 for test data set. MMCNN's age predictions were comparable to microscope-based ages yielding as good or slightly better precision. Moreover, the model outperformed classical partial least squares analysis of otolith spectra and remedied prediction bias at older ages of fish.
{"title":"The future of fish age estimation: deep machine learning coupled with Fourier transform near-infrared spectroscopy of otoliths","authors":"I. Benson, T. Helser, Giovanni Marchetti, B. Barnett","doi":"10.1139/cjfas-2023-0045","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0045","url":null,"abstract":"Our novel approach for fish age prediction uses quantitative analysis of Fourier transform near-infrared (FT-NIR) spectra of otoliths by means of multimodal convolutional neural networks (MMCNN). We integrate two key data modalities that are related to fish ages: the entire range of wavenumbers of FT-NIR spectra and corresponding biological and geospatial data for nearly 9000 walleye pollock ( Gadus chalcogrammus) specimens. The proposed model extracts informative spectral features automatically and elucidates hidden structural relationships associated with fish growth to improve age predictions. Absorbance associated with 7000 to 4000 cm−1 wavenumbers had the highest influence on model predictions followed by fish length, latitude, depth, and temperature. The optimal model resulted in good overall performance with an R2 of 0.93 and RMSE of 0.83 for training data set and R2 of 0.92 and RMSE of 0.91 for test data set. MMCNN's age predictions were comparable to microscope-based ages yielding as good or slightly better precision. Moreover, the model outperformed classical partial least squares analysis of otolith spectra and remedied prediction bias at older ages of fish.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48050182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
For many of the world's fisheries, harvest control rules (HCRs) are the main tools for supporting decision-making. We previously clarified the optimal shape of the HCR to achieve multiple fisheries management objectives (maximising average catch, reducing variation in yields, and avoiding stock collapse) and ensure robustness to estimation errors in biomass by numerically estimating the optimal values of the 21 biological reference points (BRPs) comprised in the HCR. However, for actual management, a simple but comprehensive functional form to emulate the optimal HCR is desirable, as numerical HCR optimisation with many BRPs is time-consuming. Here, we introduced three objective utility functions ( U1– U3) representing HCR performance for composite management objectives: mean–variance utility functions, where the performance indicator for variation in yields is the standard deviation ( U1) or the annual average variance ( U2) of yields, and the constant relative risk aversion utility function ( U3). We derived two equations to emulate the optimal HCRs with three adjusting parameters corresponding to the management objectives and different magnitudes of estimation errors. These equations will help stakeholders discuss desired management strategies by showing expected catch and risk by adjusting the parameter values.
{"title":"A comprehensive functional form of the optimal harvest control rule for multiple fishery management objectives","authors":"Tatsunori Yagi, T. Yamakawa","doi":"10.1139/cjfas-2022-0195","DOIUrl":"https://doi.org/10.1139/cjfas-2022-0195","url":null,"abstract":"For many of the world's fisheries, harvest control rules (HCRs) are the main tools for supporting decision-making. We previously clarified the optimal shape of the HCR to achieve multiple fisheries management objectives (maximising average catch, reducing variation in yields, and avoiding stock collapse) and ensure robustness to estimation errors in biomass by numerically estimating the optimal values of the 21 biological reference points (BRPs) comprised in the HCR. However, for actual management, a simple but comprehensive functional form to emulate the optimal HCR is desirable, as numerical HCR optimisation with many BRPs is time-consuming. Here, we introduced three objective utility functions ( U1– U3) representing HCR performance for composite management objectives: mean–variance utility functions, where the performance indicator for variation in yields is the standard deviation ( U1) or the annual average variance ( U2) of yields, and the constant relative risk aversion utility function ( U3). We derived two equations to emulate the optimal HCRs with three adjusting parameters corresponding to the management objectives and different magnitudes of estimation errors. These equations will help stakeholders discuss desired management strategies by showing expected catch and risk by adjusting the parameter values.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41548207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The recently developed approach to estimating instantaneous total mortality of coded-wire-tagged lake trout (Salvelinus namaycush) is generally applicable to catch-at-age data. We further formalized the technique to objectively incorporate the year-class and year effects into the model structure of catch-curve regression. We used this new method to compare adult mortality and year-class strength between the hatchery-stocked and wild-reared lake trout in US waters of Lake Huron, one of the Laurentian Great Lakes. Model comparisons showed no difference in adult mortality between the hatchery-stocked and wild-reared lake trout. Based on 95% confidence intervals, the estimate of adult mortality using the simple catch-curve regression with average number-at-age was not statistically different from the estimate using the linear-mixed model with individual number-at-age of multiple year-classes and sampling years. The linear-mixed model, however, also quantified lake trout year-class strength and indicated that since 2003 the increases in recruitment of wild-reared lake trout did not fully compensate for the rapid declines in recruitment of hatchery-stocked lake trout in Lake Huron.
{"title":"A generalized application of the catch-curve regression with comparisons of adult mortality and year-class strength between hatchery-stocked and wild-reared lake trout in US waters of Lake Huron","authors":"Ji X. He, C. P. Madenjian, Todd C. Wills","doi":"10.1139/cjfas-2022-0275","DOIUrl":"https://doi.org/10.1139/cjfas-2022-0275","url":null,"abstract":"The recently developed approach to estimating instantaneous total mortality of coded-wire-tagged lake trout (Salvelinus namaycush) is generally applicable to catch-at-age data. We further formalized the technique to objectively incorporate the year-class and year effects into the model structure of catch-curve regression. We used this new method to compare adult mortality and year-class strength between the hatchery-stocked and wild-reared lake trout in US waters of Lake Huron, one of the Laurentian Great Lakes. Model comparisons showed no difference in adult mortality between the hatchery-stocked and wild-reared lake trout. Based on 95% confidence intervals, the estimate of adult mortality using the simple catch-curve regression with average number-at-age was not statistically different from the estimate using the linear-mixed model with individual number-at-age of multiple year-classes and sampling years. The linear-mixed model, however, also quantified lake trout year-class strength and indicated that since 2003 the increases in recruitment of wild-reared lake trout did not fully compensate for the rapid declines in recruitment of hatchery-stocked lake trout in Lake Huron.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46908876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Kayla Kelley, E. Gilbert, C. Pennock, M. McKinstry, P. Mackinnon, S. Durst, N. R. Franssen
Fish passages are constructed to facilitate movement around barriers, but few are quantitatively evaluated for non-salmonids. We quantified the efficiency of a selective, nature-like fish passage for three native fishes, Colorado pikeminnow (Ptychocheilus lucius), flannelmouth sucker (Catostomus latipinnis), and razorback sucker (Xyrauchen texanus), in the San Juan River, NM, USA by estimating probabilities of completing three navigational phases and associated delay times. We compared passage efficiency in years when fish were captured in a trap and manually moved upstream to years when the trap was removed in the spring. All species were less efficient at navigating the attraction and exit phases compared to the ascent phase. Operating the passage without the trap generally increased passage success and shortened delay times. Mean probability of passage and delay time among species when the trap was removed ranged from 34–55% and 5–21 days, respectively. Our results suggest species- and phase-specific variation in passage efficiency and highlight the need for evaluations to aid future passage design and operation for a greater diversity of fishes.
{"title":"If you build it, will they pass? A systematic evaluation of fish passage efficiency for three large-bodied warm-water fishes","authors":"Kayla Kelley, E. Gilbert, C. Pennock, M. McKinstry, P. Mackinnon, S. Durst, N. R. Franssen","doi":"10.1139/cjfas-2023-0030","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0030","url":null,"abstract":"Fish passages are constructed to facilitate movement around barriers, but few are quantitatively evaluated for non-salmonids. We quantified the efficiency of a selective, nature-like fish passage for three native fishes, Colorado pikeminnow (Ptychocheilus lucius), flannelmouth sucker (Catostomus latipinnis), and razorback sucker (Xyrauchen texanus), in the San Juan River, NM, USA by estimating probabilities of completing three navigational phases and associated delay times. We compared passage efficiency in years when fish were captured in a trap and manually moved upstream to years when the trap was removed in the spring. All species were less efficient at navigating the attraction and exit phases compared to the ascent phase. Operating the passage without the trap generally increased passage success and shortened delay times. Mean probability of passage and delay time among species when the trap was removed ranged from 34–55% and 5–21 days, respectively. Our results suggest species- and phase-specific variation in passage efficiency and highlight the need for evaluations to aid future passage design and operation for a greater diversity of fishes.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45711144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Morten Falkegård, R. Lennox, E. Thorstad, S. Einum, P. Fiske, Ø. Garmo, Å. Garseth, H. Skoglund, M. Solberg, K. Utne, K. Vollset, L. A. Vøllestad, V. Wennevik, T. Forseth
Managers and stakeholders increasingly ask whether predation is a driving force behind the poor status of many species, and whether predator control is likely to be a successful management action to intervene. We review existing literature on Atlantic salmon Salmo salar predation and predator control, as well as general ecological theory on the role of predation in the life cycle of this iconic fish. Many bird, mammal, and fish predators target salmon at different life stages. In healthy salmon populations, predation is likely compensated for by reduced intra-specific competition during the freshwater stage. There is little evidence that predation alone has been an underlying mechanism for driving salmon populations below conservation limits. However, depending on the predator’s response to salmon abundance, predation may keep decimated populations from recovering, even when the actual causes of decline have been removed. Under such a scenario, predation control may contribute to recovery, but there are no strong examples that clearly demonstrate the efficacy of managing predators to recover threatened salmon populations, challenging further applications.
{"title":"Predation of Atlantic salmon across ontogenetic stages and impacts on populations","authors":"Morten Falkegård, R. Lennox, E. Thorstad, S. Einum, P. Fiske, Ø. Garmo, Å. Garseth, H. Skoglund, M. Solberg, K. Utne, K. Vollset, L. A. Vøllestad, V. Wennevik, T. Forseth","doi":"10.1139/cjfas-2023-0029","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0029","url":null,"abstract":"Managers and stakeholders increasingly ask whether predation is a driving force behind the poor status of many species, and whether predator control is likely to be a successful management action to intervene. We review existing literature on Atlantic salmon Salmo salar predation and predator control, as well as general ecological theory on the role of predation in the life cycle of this iconic fish. Many bird, mammal, and fish predators target salmon at different life stages. In healthy salmon populations, predation is likely compensated for by reduced intra-specific competition during the freshwater stage. There is little evidence that predation alone has been an underlying mechanism for driving salmon populations below conservation limits. However, depending on the predator’s response to salmon abundance, predation may keep decimated populations from recovering, even when the actual causes of decline have been removed. Under such a scenario, predation control may contribute to recovery, but there are no strong examples that clearly demonstrate the efficacy of managing predators to recover threatened salmon populations, challenging further applications.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44006442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Grüss, J. Thorson, O. Anderson, R. O’Driscoll, Madison Heller-Shipley, Scott E. Goodman
Spatio-temporal models are widely applied to standardise research survey data and are increasingly used to generate density maps and indices from other data sources. We developed a spatio-temporal modelling framework that integrates research survey data (treated as a “reference dataset”) and other data sources (“non-reference datasets”) while estimating spatially varying catchability for the non-reference datasets. We demonstrated it using two case studies. The first involved bottom trawl survey and observer data for spiny dogfish (Squalus acanthias) on the Chatham Rise, New Zealand. The second involved cod predators as samplers of juvenile snow crab (Chionoecetes opilio) abundance, integrated with industry-cooperative surveys and a bottom trawl research survey in the eastern Bering Sea. Our integrated models leveraged the strengths of individual data sources (the quality of the reference dataset and the quantity of non-reference data), while downweighting the influence of the non-reference datasets via the estimated spatially varying catchabilities. They allowed for the generation of annual density maps for a longer time-period, and for the provision of one single index rather than multiple indices each covering a shorter time-period.
{"title":"Spatially varying catchability for integrating research survey data with other data sources: case studies involving observer samples, industry-cooperative surveys, and predators-as-samplers","authors":"A. Grüss, J. Thorson, O. Anderson, R. O’Driscoll, Madison Heller-Shipley, Scott E. Goodman","doi":"10.1139/cjfas-2023-0051","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0051","url":null,"abstract":"Spatio-temporal models are widely applied to standardise research survey data and are increasingly used to generate density maps and indices from other data sources. We developed a spatio-temporal modelling framework that integrates research survey data (treated as a “reference dataset”) and other data sources (“non-reference datasets”) while estimating spatially varying catchability for the non-reference datasets. We demonstrated it using two case studies. The first involved bottom trawl survey and observer data for spiny dogfish (Squalus acanthias) on the Chatham Rise, New Zealand. The second involved cod predators as samplers of juvenile snow crab (Chionoecetes opilio) abundance, integrated with industry-cooperative surveys and a bottom trawl research survey in the eastern Bering Sea. Our integrated models leveraged the strengths of individual data sources (the quality of the reference dataset and the quantity of non-reference data), while downweighting the influence of the non-reference datasets via the estimated spatially varying catchabilities. They allowed for the generation of annual density maps for a longer time-period, and for the provision of one single index rather than multiple indices each covering a shorter time-period.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46110418","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Life histories of anadromous and landlocked sea lamprey are similar, though landlocked populations lack seawater exposure, likely experiencing relaxed selection on SW survival traits. This study investigated seawater osmoregulation in juvenile lamprey from one anadromous and three landlocked populations from the Great Lakes and Lake Champlain. Juveniles in all populations had strongly elevated gill Na+/K+-ATPase activity compared to larvae, indicating all populations underwent osmoregulatory changes associated with metamorphosis. Survival in seawater was high in anadromous lamprey (90%) and highly variable among landlocked populations (40-100%). Plasma ions levels were higher and hematocrit was lower after seawater exposure in landlocked compared to anadromous lamprey. Freshwater gill ion transporter (H+-ATPase; Na+:Cl- cotransporter) mRNA levels were higher in freshwater and remained high after seawater exposure in landlocked relative to anadromous juveniles. Landlocked lamprey had 24-33% higher gill Na+:K+:2Cl- cotransporter abundance after seawater exposure compared to anadromous lamprey. Our results indicate ionoregulatory differences that are consistent with relaxed selection on traits for seawater entry and positive selection on freshwater traits in landlocked populations, suggestive of a recent Great Lakes invasion.
{"title":"Landlocked populations have small but detectable differences in ionoregulatory physiology compared to anadromous sea lamprey, Petromyzon marinus","authors":"Jessica L Norstog, S. McCormick","doi":"10.1139/cjfas-2022-0242","DOIUrl":"https://doi.org/10.1139/cjfas-2022-0242","url":null,"abstract":"Life histories of anadromous and landlocked sea lamprey are similar, though landlocked populations lack seawater exposure, likely experiencing relaxed selection on SW survival traits. This study investigated seawater osmoregulation in juvenile lamprey from one anadromous and three landlocked populations from the Great Lakes and Lake Champlain. Juveniles in all populations had strongly elevated gill Na+/K+-ATPase activity compared to larvae, indicating all populations underwent osmoregulatory changes associated with metamorphosis. Survival in seawater was high in anadromous lamprey (90%) and highly variable among landlocked populations (40-100%). Plasma ions levels were higher and hematocrit was lower after seawater exposure in landlocked compared to anadromous lamprey. Freshwater gill ion transporter (H+-ATPase; Na+:Cl- cotransporter) mRNA levels were higher in freshwater and remained high after seawater exposure in landlocked relative to anadromous juveniles. Landlocked lamprey had 24-33% higher gill Na+:K+:2Cl- cotransporter abundance after seawater exposure compared to anadromous lamprey. Our results indicate ionoregulatory differences that are consistent with relaxed selection on traits for seawater entry and positive selection on freshwater traits in landlocked populations, suggestive of a recent Great Lakes invasion.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43546751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
J. Burbank, François Turcotte, François-Étienne Sylvain, Nicolas Rolland
Despite the importance of recruitment for population dynamics and assessing stock status, limited information exists on the relative influence of various ecosystem and demographic factors on the recruitment dynamics of marine fishes. We develop a statistical framework to identify the ecosystem and demographic factors influencing the recruitment and of marine fishes and facilitate improved predictions of recruitment. We demonstrate the approach by examining the relative influence of ecosystem and demographic factors on the recruitment of southern Gulf of St. Lawrence spring and fall spawning Atlantic Herring (Clupea harengus) stocks, highlighting the benefit of considering multiple factors to better understand recruitment trends. We found different combinations of biological and physical ecosystem factors along with demographic had a significant influence on the recruitment and recruitment rate of spring and fall spawning herring. The study emphasizes the value of considering ecosystem characteristics when examining recruitment, provides a framework for researchers to investigate and model recruitment of other fish populations, and supports the continued development and implementation of ecosystem based fisheries management approaches for species such as Atlantic Herring.
{"title":"A statistical framework for identifying the relative importance of ecosystem processes and demographic factors on fish recruitment, with application to Atlantic Herring (Clupea harengus) in the southern Gulf of St. Lawrence","authors":"J. Burbank, François Turcotte, François-Étienne Sylvain, Nicolas Rolland","doi":"10.1139/cjfas-2023-0081","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0081","url":null,"abstract":"Despite the importance of recruitment for population dynamics and assessing stock status, limited information exists on the relative influence of various ecosystem and demographic factors on the recruitment dynamics of marine fishes. We develop a statistical framework to identify the ecosystem and demographic factors influencing the recruitment and of marine fishes and facilitate improved predictions of recruitment. We demonstrate the approach by examining the relative influence of ecosystem and demographic factors on the recruitment of southern Gulf of St. Lawrence spring and fall spawning Atlantic Herring (Clupea harengus) stocks, highlighting the benefit of considering multiple factors to better understand recruitment trends. We found different combinations of biological and physical ecosystem factors along with demographic had a significant influence on the recruitment and recruitment rate of spring and fall spawning herring. The study emphasizes the value of considering ecosystem characteristics when examining recruitment, provides a framework for researchers to investigate and model recruitment of other fish populations, and supports the continued development and implementation of ecosystem based fisheries management approaches for species such as Atlantic Herring.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49514924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
B. Shuter, S. Milne, L. Hrenchuk, D. D. De Kerckhove, M. Rennie
Population abundance is a critical metric in fisheries and conservation but it is difficult to measure accurately. Existing estimation methods present significant challenges: mark-recapture methods are time- and labour-intensive, and hydroacoustic echo counting methods face issues with target identity and the habitat types where they can be effectively applied. We present a new methodology for abundance estimation that can improve the reliability of echo counting methods. Split beam hydroacoustic survey data is integrated with telemetry data from fish bearing acoustic transponder tags. These tags are counted by a spatially and temporally concurrent multibeam acoustic survey to produce mark-recapture abundance estimates. We assessed this approach on four wild lake trout populations, ranging in abundance from ~ 200 to ~ 3000 adults. Our abundance estimates were consistent with those derived from conventional Schnabel and Jolly-Seber mark-recapture studies. We show that the precision achievable with this method in one year of field work rivals that provided by long term (> 10 years), continuous mark-recapture studies. We also discuss other ecological questions that could be addressed with this approach.
{"title":"Integrating Hydro-acoustic and Telemetry Surveys to Estimate Fish Abundance: A New Approach to an Old Problem","authors":"B. Shuter, S. Milne, L. Hrenchuk, D. D. De Kerckhove, M. Rennie","doi":"10.1139/cjfas-2022-0183","DOIUrl":"https://doi.org/10.1139/cjfas-2022-0183","url":null,"abstract":"Population abundance is a critical metric in fisheries and conservation but it is difficult to measure accurately. Existing estimation methods present significant challenges: mark-recapture methods are time- and labour-intensive, and hydroacoustic echo counting methods face issues with target identity and the habitat types where they can be effectively applied. We present a new methodology for abundance estimation that can improve the reliability of echo counting methods. Split beam hydroacoustic survey data is integrated with telemetry data from fish bearing acoustic transponder tags. These tags are counted by a spatially and temporally concurrent multibeam acoustic survey to produce mark-recapture abundance estimates. We assessed this approach on four wild lake trout populations, ranging in abundance from ~ 200 to ~ 3000 adults. Our abundance estimates were consistent with those derived from conventional Schnabel and Jolly-Seber mark-recapture studies. We show that the precision achievable with this method in one year of field work rivals that provided by long term (> 10 years), continuous mark-recapture studies. We also discuss other ecological questions that could be addressed with this approach.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46016108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Bradley E. Howell, Giulio Navarroli, Eric J. Mullen, S. Cooke, C. Hasler
We examined behaviour and physiology of lake trout (Salvelinus namaycush) following ice-angling. Fish were ice-angled and placed in a water-filled tub for 0.5, 4, and 6h to recover (n=19). Reflex impairment and physiological status were assessed repeatedly for every individual. Longer fight times lead to higher lactate and glucose, and lower extracellular pH 0.5h post-angling. Loss of orientation was the most common reflex impairment (84% of fish) 4h post-angling. Mortality (36.8%) was observed during the study; however, variation in handling, barotrauma, and issues with sampling may have confounded angling effects. To determine if barotrauma impacted impairment and mortality, lake trout at a later sampling date (n=29) were exposed to air for either 60, 120, 180, 240, 300, or 420s before assessment (3.4% mortality). For fish air exposed for 300s or more, 14% lost orientation during immediate assessment. Bloating occurred in 20% of fish air exposed for 60s. An air exposure duration of 420s significantly impaired reflexes. Recreationally caught lake trout show behavioural and physiological impairment with such impairments magnified by extended air exposure.
{"title":"Lake trout reflex impairment and physiological status following ice-angling","authors":"Bradley E. Howell, Giulio Navarroli, Eric J. Mullen, S. Cooke, C. Hasler","doi":"10.1139/cjfas-2023-0037","DOIUrl":"https://doi.org/10.1139/cjfas-2023-0037","url":null,"abstract":"We examined behaviour and physiology of lake trout (Salvelinus namaycush) following ice-angling. Fish were ice-angled and placed in a water-filled tub for 0.5, 4, and 6h to recover (n=19). Reflex impairment and physiological status were assessed repeatedly for every individual. Longer fight times lead to higher lactate and glucose, and lower extracellular pH 0.5h post-angling. Loss of orientation was the most common reflex impairment (84% of fish) 4h post-angling. Mortality (36.8%) was observed during the study; however, variation in handling, barotrauma, and issues with sampling may have confounded angling effects. To determine if barotrauma impacted impairment and mortality, lake trout at a later sampling date (n=29) were exposed to air for either 60, 120, 180, 240, 300, or 420s before assessment (3.4% mortality). For fish air exposed for 300s or more, 14% lost orientation during immediate assessment. Bloating occurred in 20% of fish air exposed for 60s. An air exposure duration of 420s significantly impaired reflexes. Recreationally caught lake trout show behavioural and physiological impairment with such impairments magnified by extended air exposure.","PeriodicalId":9515,"journal":{"name":"Canadian Journal of Fisheries and Aquatic Sciences","volume":" ","pages":""},"PeriodicalIF":2.4,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42178709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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